On Tue, 22 Jul 2025, Tomasz Kamiński wrote:
> Adds negative tests for preconditions on inserting into a full
> inplace_vector and erasing non-existent elementsi at compile-time.
> This ensures coverage for the inplace_vector<T, 0> specialization.
>
> Also extends element access tests to cover front() and back()
> methods, and const and mutable overloads for all accesses.
>
> PR libstdc++/119137
>
> libstdc++-v3/ChangeLog:
>
> * testsuite/23_containers/inplace_vector/access/elem.cc: Cover
> front and back methods and const calls.
> * testsuite/23_containers/inplace_vector/access/elem_neg.cc:
> Likewise.
> * testsuite/23_containers/inplace_vector/modifiers/erase_neg.cc:
> New test.
> * testsuite/23_containers/inplace_vector/modifiers/single_insert_neg.cc:
> New test.
> ---
> v2 removes accidentally added access/single_insert.cc file with copy of
> content
> of modifiers/single_insert.cc.
LGTM
>
> .../inplace_vector/access/elem.cc | 35 ++++++++-------
> .../inplace_vector/access/elem_neg.cc | 44 ++++++++++++-------
> .../inplace_vector/modifiers/erase_neg.cc | 43 ++++++++++++++++++
> .../modifiers/single_insert_neg.cc | 42 ++++++++++++++++++
> 4 files changed, 132 insertions(+), 32 deletions(-)
> create mode 100644
> libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/erase_neg.cc
> create mode 100644
> libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/single_insert_neg.cc
>
> diff --git
> a/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem.cc
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem.cc
> index 8b1f492dd51..bc06aa09425 100644
> --- a/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem.cc
> +++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem.cc
> @@ -41,11 +41,17 @@ test_out_of_capacity()
> #endif
> }
>
> -template<typename T>
> +
> +template<bool Const, typename T, size_t N>
> +using InplaceVector = std::conditional_t<Const,
> + const std::inplace_vector<T, N>,
> + std::inplace_vector<T, N>>;
> +
> +template<bool Const, typename T>
> constexpr void
> test_access()
> {
> - std::inplace_vector<T, 10> v{1, 2, 3, 4, 5};
> + InplaceVector<Const, T, 10> v{1, 2, 3, 4, 5};
>
> auto& e0a = v[0];
> auto& e0b = v.at(0);
> @@ -53,23 +59,26 @@ test_access()
> VERIFY( &e0a == &e0b );
> VERIFY( &e0a == &e0c );
> VERIFY( &e0a == &v.begin()[0] );
> + VERIFY( &e0a == &v.cbegin()[0] );
> VERIFY( &e0a == v.data() );
> VERIFY( e0a == T(1) );
>
> auto& e3a = v[2];
> - auto& e3b = std::as_const(v).at(2);
> + auto& e3b = v.at(2);
> VERIFY( &e3a == &e3b );
> VERIFY( &e3a == &v.begin()[2] );
> - VERIFY( &e3a == std::as_const(v).data() + 2 );
> + VERIFY( &e3a == &v.cbegin()[2] );
> + VERIFY( &e3a == v.data() + 2 );
> VERIFY( e3a == T(3) );
>
> - auto& e4a = as_const(v)[4];
> + auto& e4a = v[4];
> auto& e4b = v.at(4);
> - auto& e4c = as_const(v).back();
> + auto& e4c = v.back();
> VERIFY( &e4a == &e4b );
> VERIFY( &e4a == &e4c );
> + VERIFY( &e4a == &v.begin()[4] );
> VERIFY( &e4a == &v.cbegin()[4] );
> - VERIFY( &e4a == as_const(v).data() + 4 );
> + VERIFY( &e4a == v.data() + 4 );
> VERIFY( e4a == T(5) );
>
> #ifdef __cpp_exceptions
> @@ -88,15 +97,6 @@ test_access()
> catch (std::out_of_range const&)
> {
> }
> -
> - try
> - {
> - (void)as_const(v).at(7);
> - VERIFY(false);
> - }
> - catch (std::out_of_range const&)
> - {
> - }
> #endif
> }
>
> @@ -105,7 +105,8 @@ int main()
> auto test_all = [] {
> test_out_of_capacity<0, int>();
> test_out_of_capacity<4, int>();
> - test_access<int>();
> + test_access<true, int>();
> + test_access<false, int>();
> return true;
> };
>
> diff --git
> a/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem_neg.cc
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem_neg.cc
> index 7e6780163ab..b2bff0d6387 100644
> --- a/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem_neg.cc
> +++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/access/elem_neg.cc
> @@ -2,49 +2,63 @@
>
> #include <inplace_vector>
>
> -template<size_t N, typename T>
> +template<bool Const, typename T, size_t N>
> +using InplaceVector
> + = std::conditional_t<Const,
> + const std::inplace_vector<T, N>,
> + std::inplace_vector<T, N>>;
> +
> +template<bool Const, size_t N, typename T>
> constexpr bool
> test_front_on_empty()
> {
> - std::inplace_vector<T, N> v;
> + InplaceVector<Const, T, N> v;
> (void)v.front(); // { dg-error "in 'constexpr' expansion of" }
> return true;
> }
>
> -template<size_t N, typename T>
> +template<bool Const, size_t N, typename T>
> constexpr bool
> test_back_on_empty()
> {
> - std::inplace_vector<T, N> v;
> + InplaceVector<Const, T, N> v;
> (void)v.back(); // { dg-error "in 'constexpr' expansion of" }
> return true;
> }
>
> -template<size_t N, typename T>
> +template<bool Const, size_t N, typename T>
> constexpr bool
> test_out_of_capacity()
> {
> - std::inplace_vector<T, N> v;
> + InplaceVector<Const, T, N> v;
> (void)v[N+2]; // { dg-error "in 'constexpr' expansion of" }
> return true;
> }
>
> -template<typename T>
> +template<bool Const, typename T>
> constexpr bool
> test_out_of_size()
> {
> - std::inplace_vector<T, 10> v{1, 2, 3, 4, 5};
> + InplaceVector<Const, T, 10> v{1, 2, 3, 4, 5};
> (void)v[7]; // { dg-error "in 'constexpr' expansion of" }
> return true;
> }
>
> -static_assert(test_front_on_empty<0, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_front_on_empty<4, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_back_on_empty<0, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_back_on_empty<4, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_out_of_capacity<0, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_out_of_capacity<4, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> -static_assert(test_out_of_size<int>()); // { dg-error "in 'constexpr'
> expansion of" }
> +static_assert(test_front_on_empty<false, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_front_on_empty<false, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_back_on_empty<false, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_back_on_empty<false, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_capacity<false, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_capacity<false, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_size<false, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +
> +static_assert(test_front_on_empty<true, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_front_on_empty<true, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_back_on_empty<true, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_back_on_empty<true, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_capacity<true, 0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_capacity<true, 4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_out_of_size<true, int>()); // { dg-error "in
> 'constexpr' expansion of" }
>
> // { dg-prune-output "non-constant condition for static assertion" }
> // { dg-prune-output "is not a constant expression" }
> diff --git
> a/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/erase_neg.cc
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/erase_neg.cc
> new file mode 100644
> index 00000000000..a1f43b3b53b
> --- /dev/null
> +++
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/erase_neg.cc
> @@ -0,0 +1,43 @@
> +// { dg-do compile { target c++26 } }
> +
> +#include <inplace_vector>
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_pop_back_on_empty()
> +{
> + std::inplace_vector<T, N> v;
> + v.pop_back(); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_erase_begin_on_empty()
> +{
> + std::inplace_vector<T, N> v;
> + v.erase(v.begin()); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_erase_end(size_t size = 0)
> +{
> + std::inplace_vector<T, N> v(size, T());
> + v.erase(v.end()); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +static_assert(test_pop_back_on_empty<0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_pop_back_on_empty<4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_erase_begin_on_empty<0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_erase_begin_on_empty<4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_erase_end<0, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> +static_assert(test_erase_end<4, int>()); // { dg-error "in 'constexpr'
> expansion of" }
> +static_assert(test_erase_end<4, int>(2)); // { dg-error "in 'constexpr'
> expansion of" }
> +static_assert(test_erase_end<4, int>(4)); // { dg-error "in 'constexpr'
> expansion of" }
> +
> +// { dg-prune-output "non-constant condition for static assertion" }
> +// { dg-prune-output "is not a constant expression" }
> +// { dg-prune-output "call to non-'constexpr' function" }
> diff --git
> a/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/single_insert_neg.cc
>
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/single_insert_neg.cc
> new file mode 100644
> index 00000000000..0552b8c2b7d
> --- /dev/null
> +++
> b/libstdc++-v3/testsuite/23_containers/inplace_vector/modifiers/single_insert_neg.cc
> @@ -0,0 +1,42 @@
> +// { dg-do compile { target c++26 } }
> +
> +#include <inplace_vector>
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_unchecked_emplace_back()
> +{
> + std::inplace_vector<T, N> v(N, T(1));
> + v.unchecked_emplace_back(); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_push_back_lvalue()
> +{
> + auto val = T();;
> + std::inplace_vector<T, N> v(N, T(1));
> + v.unchecked_push_back(val); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +template<size_t N, typename T>
> +constexpr bool
> +test_push_back_rvalue()
> +{
> + std::inplace_vector<T, N> v(N, T(1));
> + v.unchecked_push_back(T()); // { dg-error "in 'constexpr' expansion of" }
> + return true;
> +}
> +
> +static_assert(test_unchecked_emplace_back<0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_unchecked_emplace_back<4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_push_back_lvalue<0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_push_back_lvalue<4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_push_back_rvalue<0, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +static_assert(test_push_back_rvalue<4, int>()); // { dg-error "in
> 'constexpr' expansion of" }
> +
> +// { dg-prune-output "non-constant condition for static assertion" }
> +// { dg-prune-output "is not a constant expression" }
> +// { dg-prune-output "call to non-'constexpr' function" }
> --
> 2.49.0
>
>
